Concrete is a synthetic material made mostly from rock. Concrete can be used to create the outside walls of a building's basement, as shown below.

a concrete foundation poured for the basement of a house

Other materials could also be used for making the basement. Some properties of several materials are listed below.

Concrete Rock Wood
cracks under stress
waterproof
can be poured to make any shape
hard and strong
lets water through spaces between rocks
limited by sizes of available rocks
can decompose when wet
absorbs water
may be eaten by insects

Which statement best explains why the outside walls of a basement are most commonly made of concrete instead of the other materials listed?
A.
Concrete lasts a long time and keeps water out.
B.
Concrete can change its shape if the ground shifts.
C.
Concrete is strengthened by contact with water.
D.
Concrete does not use up natural resources.